It turns out that by default the dev mode vault server will attempt to interact with the
filesystem to store the provided root token. If multiple vault instances are running
they'll all awkwardly share the filesystem and if timing results in one server stopping
while another one is starting then the starting one will error with:
Error initializing Dev mode: rename /home/circleci/.vault-token.tmp /home/circleci/.vault-token: no such file or directory
This change uses `-dev-no-store-token` to bypass that source of flakes. Also the
stdout/stderr from the vault process is included if the test fails.
The introduction of more `t.Parallel` use in https://github.com/hashicorp/consul/pull/15669
increased the likelihood of this failure, but any of the tests with multiple vaults in use
(or running multiple package tests in parallel that all use vault) were eventually going
to flake on this.